Metabolic health
Delta-6 desaturase index A and B (D6D)
D6D activity index
Included in Complete.
Compare membershipsTwo ways to estimate the first step in omega-6 processing.
Delta-6 desaturase is an enzyme that adds a double bond, a kind of kink, to fats. It starts the conversion of linoleic acid into longer omega-6 fats, and these indices estimate its activity using ratios calculated from your fatty acid results.
There are two common versions of this index.
Delta-6 desaturase turns linoleic acid into GLA, which is then lengthened into DGLA. Labs may report one ratio using GLA over linoleic acid and another using DGLA over linoleic acid, and formulas vary by lab. The same enzyme also works on omega-3 fats.
Both are indirect estimates shaped by diet and genes (including the FADS2 gene). In observational studies, a higher index has been linked with insulin resistance and higher type 2 diabetes risk. This is mainly a research measure.
Questions
What does a higher delta-6 desaturase index mean?
It may suggest more conversion of linoleic acid into longer omega-6 fats, though diet can shift it as well. In one study, this index was less consistent across different blood fractions than some other indices, so it's best read with your other fatty acids and metabolic markers.
Why might index A and index B differ?
They use different products in the calculation, so they can respond differently to diet, supplements, and individual metabolism. Reading both together gives a fuller picture.
Sources and references
- Warensjö et al., Associations between estimated fatty acid desaturase activities in serum lipids and adipose tissue in humans (Lipids Health Dis, 2009)
- Kröger and Schulze, Delta-5 and delta-6 desaturase activity and type 2 diabetes (Curr Opin Lipidol, 2012)
- Czumaj and Śledziński, Biological role of unsaturated fatty acid desaturases in health and disease (Nutrients, 2020)